The invention relates to a fuel limiting apparatus for an internal combustion vehicle and, more specifically, to an apparatus used to modify an internal combustion vehicle so that the maximum rate of fuel supplied to the engine is restricted according to a preselected schedule dependent upon the speed of the vehicle, the gear state of the transmission, or other operating conditions.
In the manufacture of internal combustion vehicles, the engines are typically sized to provide power to meet the maximum requirements of the particular application and design constraints of the vehicle. Operating conditions of the vehicle, however, vary over a wide range of power demands, particularly when considerations are made for fuel economy and reduction of polluting emissions from the vehicle. For example, as is well known, substantial amounts of fuel are wasted by full acceleration starts wherein the engine is over-fueled under the transient conditions. It is just being understood and appreciated that such full acceleration starts also result in substantial increases of emissions from the engine, particularly in the form of hydrocarbons and particulates. In an over-fuel condition, the engine is unable to burn fully all of the fuel with the result that uncombusted hydrocarbons are emitted. Such conditions also reduce the temperature of the combustion chamber which leads to an increase in the formation of particulate emissions.
The use of the full capacity of the engine power, particularly for high acceleration at low speeds, produces excessive stresses on the engine, the drive train of the vehicle, the suspension, and other components. While these effects have been long recognized and discouraged both by public agencies as well as private fleet owners, there has been heretofore no suitable way of forcing compliance with the recommended guidelines.